Commit Overhead vs Throughput
Commit Overhead vs Throughput
Analysis of commit protocol overhead as percentage of total transaction time.
Overhead = (commit_latency / total_latency) × 100
This represents time spent in retries, exponential backoff, and manifest I/O.
Values shown as mean ± standard deviation across seeds.
real_conflict_probability = 0.0
| Throughput (c/s) | Success Rate (%) | Mean Overhead (%) | P50 Overhead (%) | P95 Overhead (%) | P99 Overhead (%) |
|---|---|---|---|---|---|
| 0.2 ± 0.0 | 100.0 ± 0.0 | 0.3 ± 0.0 | 0.3 ± 0.0 | 0.5 ± 0.0 | 0.6 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.8 ± 0.0 | 0.8 ± 0.0 | 1.1 ± 0.0 | 1.2 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.5 ± 0.0 | 1.4 ± 0.0 | 1.8 ± 0.1 | 2.0 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.8 ± 0.0 | 2.8 ± 0.0 | 3.3 ± 0.1 | 3.5 ± 0.1 |
| 5.0 ± 0.0 | 100.0 ± 0.0 | 7.0 ± 0.1 | 7.0 ± 0.1 | 7.7 ± 0.1 | 8.1 ± 0.1 |
| 9.5 ± 0.1 | 96.8 ± 0.2 | 13.4 ± 0.1 | 13.4 ± 0.1 | 14.1 ± 0.1 | 14.5 ± 0.1 |
| 13.7 ± 0.0 | 69.2 ± 0.1 | 19.3 ± 0.0 | 19.3 ± 0.0 | 19.9 ± 0.0 | 20.3 ± 0.1 |
| 16.0 ± 0.0 | 31.8 ± 0.0 | 22.5 ± 0.0 | 22.5 ± 0.0 | 23.0 ± 0.0 | 23.3 ± 0.0 |
| 16.9 ± 0.0 | 16.5 ± 0.1 | 23.9 ± 0.0 | 23.8 ± 0.0 | 24.3 ± 0.0 | 24.5 ± 0.0 |
real_conflict_probability = 0.1
| Throughput (c/s) | Success Rate (%) | Mean Overhead (%) | P50 Overhead (%) | P95 Overhead (%) | P99 Overhead (%) |
|---|---|---|---|---|---|
| 0.2 ± 0.0 | 100.0 ± 0.0 | 0.4 ± 0.0 | 0.3 ± 0.0 | 0.7 ± 0.1 | 1.0 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.8 ± 0.0 | 0.8 ± 0.0 | 1.2 ± 0.0 | 1.5 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.5 ± 0.0 | 1.5 ± 0.0 | 1.9 ± 0.0 | 2.4 ± 0.1 |
| 2.0 ± 0.1 | 100.0 ± 0.0 | 2.9 ± 0.1 | 2.8 ± 0.1 | 3.4 ± 0.1 | 3.8 ± 0.1 |
| 4.9 ± 0.0 | 99.9 ± 0.0 | 7.1 ± 0.1 | 7.0 ± 0.1 | 7.8 ± 0.1 | 8.4 ± 0.1 |
| 9.5 ± 0.0 | 95.8 ± 0.1 | 13.4 ± 0.1 | 13.4 ± 0.1 | 14.3 ± 0.1 | 15.0 ± 0.1 |
| 13.4 ± 0.0 | 67.4 ± 0.3 | 18.9 ± 0.1 | 18.9 ± 0.1 | 19.8 ± 0.0 | 20.4 ± 0.1 |
| 15.6 ± 0.0 | 31.2 ± 0.1 | 22.2 ± 0.0 | 22.1 ± 0.0 | 22.9 ± 0.0 | 23.4 ± 0.0 |
| 16.7 ± 0.0 | 16.2 ± 0.1 | 23.6 ± 0.0 | 23.5 ± 0.0 | 24.3 ± 0.0 | 24.7 ± 0.0 |
real_conflict_probability = 0.3
| Throughput (c/s) | Success Rate (%) | Mean Overhead (%) | P50 Overhead (%) | P95 Overhead (%) | P99 Overhead (%) |
|---|---|---|---|---|---|
| 0.2 ± 0.0 | 100.0 ± 0.0 | 0.4 ± 0.0 | 0.3 ± 0.0 | 0.9 ± 0.1 | 1.2 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.9 ± 0.0 | 0.8 ± 0.0 | 1.5 ± 0.0 | 1.8 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.6 ± 0.0 | 1.5 ± 0.0 | 2.2 ± 0.0 | 2.6 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 3.0 ± 0.0 | 2.9 ± 0.0 | 3.7 ± 0.1 | 4.3 ± 0.1 |
| 4.9 ± 0.1 | 99.9 ± 0.0 | 7.2 ± 0.1 | 7.1 ± 0.1 | 8.1 ± 0.1 | 8.9 ± 0.1 |
| 9.2 ± 0.0 | 93.6 ± 0.1 | 13.3 ± 0.0 | 13.2 ± 0.0 | 14.5 ± 0.0 | 15.4 ± 0.1 |
| 12.6 ± 0.0 | 64.0 ± 0.2 | 18.1 ± 0.0 | 18.0 ± 0.0 | 19.3 ± 0.0 | 20.1 ± 0.1 |
| 14.9 ± 0.0 | 29.8 ± 0.1 | 21.4 ± 0.0 | 21.3 ± 0.0 | 22.4 ± 0.0 | 23.0 ± 0.0 |
| 16.1 ± 0.0 | 15.6 ± 0.0 | 23.0 ± 0.0 | 22.9 ± 0.0 | 23.9 ± 0.0 | 24.5 ± 0.0 |
real_conflict_probability = 0.5
| Throughput (c/s) | Success Rate (%) | Mean Overhead (%) | P50 Overhead (%) | P95 Overhead (%) | P99 Overhead (%) |
|---|---|---|---|---|---|
| 0.2 ± 0.0 | 100.0 ± 0.0 | 0.4 ± 0.0 | 0.4 ± 0.0 | 1.0 ± 0.1 | 1.3 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.9 ± 0.0 | 0.9 ± 0.0 | 1.5 ± 0.1 | 1.9 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.7 ± 0.0 | 1.6 ± 0.0 | 2.3 ± 0.1 | 2.8 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 3.1 ± 0.0 | 3.0 ± 0.0 | 3.9 ± 0.1 | 4.5 ± 0.1 |
| 4.9 ± 0.0 | 99.8 ± 0.1 | 7.4 ± 0.0 | 7.2 ± 0.0 | 8.5 ± 0.0 | 9.4 ± 0.1 |
| 8.9 ± 0.0 | 90.5 ± 0.1 | 13.1 ± 0.0 | 12.9 ± 0.0 | 14.5 ± 0.0 | 15.6 ± 0.0 |
| 11.8 ± 0.0 | 60.1 ± 0.2 | 17.3 ± 0.0 | 17.1 ± 0.0 | 18.7 ± 0.0 | 19.6 ± 0.0 |
| 14.0 ± 0.0 | 28.0 ± 0.1 | 20.4 ± 0.0 | 20.3 ± 0.0 | 21.7 ± 0.0 | 22.4 ± 0.0 |
| 15.3 ± 0.0 | 14.9 ± 0.0 | 22.2 ± 0.0 | 22.1 ± 0.0 | 23.3 ± 0.0 | 23.9 ± 0.0 |
Interpretation
- Low overhead (<10%): System operating efficiently, minimal contention
- Medium overhead (10-30%): Moderate contention, acceptable performance
- High overhead (30-50%): High contention, commit protocol becoming significant
- Very high overhead (>50%): Commit protocol dominates, system saturated
Values shown as mean ± standard deviation across multiple seeds. At saturation, overhead can exceed 50%, meaning more time is spent retrying commits than executing transactions!